Heretofore various catalysts have been known for the hydration of olefins, and attempts have been made to use solid catalysts because of their ease of separation and recovery from the reaction product. Usually the hydration of an olefin is favored when the temperature is low and the pressure is high. However, such a reaction condition is not practical because the known solid catalysts such as silica, alumina, silica-alumina, mordenite, and zeolite become deactivated by liquid water which is formed in the reaction system.
On the other hand, a hydration process is known which employs a cation-exchange resin such as sulfonated styrene-divinylbenzene copolymer as a catalyst. This catalyst exhibits a comparatively high activity for hydration under the condition where there is liquid water. However, it has a drawback. Namely, it irreversibly liberates sulfonic acid groups and becomes greatly deactivated when the reaction temperature is increased, say, above 120.degree. C., so as to obtain the industrially desirable reaction rate. The liberated sulfonic acid groups corrode the apparatus. The deactivated catalyst cannot be regenerated by calcination which is commonly employed for inorganic solid catalysts.
Under these circumstances, there has recently been proposed a process for hydrating an olefin by using a specific crystalline alumino-silicate. (U.S. Pat. No. 4,214,107, and Japanese Patent Laid-open No. 70828/1982.) The proposed process, however, is not practical because the catalyst does not have a sufficiently high catalytic activity. See also Japanese Laid-open No. 826244.
Attempts have been made to perform hydration with a solid catalyst in the presence of a solvent in order to improve the efficiency of hydration. A known solvent for such a purpose is a sulfone-containing solution, see Japanese Patent Laid-open Nos. 10802/1982 and 7605/1978 and equivalent British Pat. No. 1,518,461 and U.S. Pat. No. 4,270,011. It has also been proposed to use an oxy acid or derivative thereof as a solvent, see U.S. Pat. Nos. 4,358,626 and 4,284,831 incorporated by reference. In these processes, the solid catalyst is substantially a cation-exchange resin, and they suffer from disadvantages inherent in the use of a cation-exchange resin.
It is an object of this invention to provide a process for hydrating an olefin with a highly active solid catalyst/solvent combination. Applicants have found that this object can be achieved by using as a catalyst hydrogen-type mordenite or hydrogen-type zeolite Y having a specific silica/alumina ratio in the presence of a sulfone or by using as a catalyst hydrogen-type crystalline aluminosilicate having a specific crystal structure and said specific silica/alumina ratio in the presence of an oxy acid or derivative thereof.